Negative electrode and electrochemical apparatus containing same, and electronic apparatus

Abstract

A negative electrode includes a negative current collector, a first negative active material layer and a second negative active material layer. The first negative active material layer is arranged on one side of a first portion of the negative current collector, and the second negative active material layers are arranged on two sides of a second portion, different from the first portion, of the negative current collector. A ratio of a weight per unit area of the first negative active material layer to a weight per unit area of the second negative active material layer on the negative current collector is 0.47 to 0.52, and a ratio of a compacted density of the first negative active material layer to a compacted density of the second negative active material layer is 0.9 to 1.1.

What is claimed is: 
     
         1 . An electrochemical apparatus, comprising:
 a positive electrode;   a separator; and   a negative electrode;   wherein the negative electrode comprises a negative current collector, a first negative active material layer, wherein the first negative active material layer is arranged on one side of a first portion of the negative current collector; and a second negative active material layer, wherein the second negative active material layers are arranged on two sides of a second portion of the negative current collector, the second portion of the negative current collector is adjacent to the first portion of the negative current collector,   wherein a ratio of a compacted density of the first negative active material layer to a compacted density of the second negative active material layer is 0.9 to 1.1;   wherein a thickness of the first negative active material layer is 40 μm to 60 μm.   
     
     
         2 . The electrochemical apparatus according to  claim 1 , wherein the first negative active material layer and the second negative active material layer each independently comprise a silicon-based material and graphite; wherein the silicon-based material is at least one selected from the group consisting of silicon oxide, silicon carbon, and a combination thereof. 
     
     
         3 . The electrochemical apparatus according to  claim 2 , wherein based on a total weight of the silicon-based material and the graphite, a weight of the silicon-based material in the first negative active material layer and the second negative active material layer is greater than or equal to 5% and less than 100%. 
     
     
         4 . The electrochemical apparatus according to  claim 2 , wherein a form of the silicon-based material comprises a crystalline state, an amorphous state, or a combination thereof. 
     
     
         5 . The electrochemical apparatus according to  claim 2 , wherein a particle size Dv 50  of a negative active material in the first negative active material layer is 8.0 μm to 20 μm, and a particle size Dv 50  of a negative active material in the second negative active material layer is 8.0 μm to 20 μm. 
     
     
         6 . The electrochemical apparatus according to  claim 2 , wherein for the silicon-based material, a ratio of a peak height at a wavenumber of 500 cm −1+−10  cm −1  to a peak height at a wavenumber of 1350 cm −1+10  cm −1  in a Raman spectrum is greater than 0. 
     
     
         7 . The electrochemical apparatus according to  claim 2 , wherein the silicon-based material further comprises a carbon coating layer. 
     
     
         8 . The electrochemical apparatus according to  claim 2 , wherein the first negative active material layer and the second negative active material layer each independently comprise a binder and a conductive agent;
 wherein the binder comprises at least one material selected from the group consisting of polyacrylate, polyimide, polyamide, polyamideimide, polyvinylidene fluoride, styrene-butadiene rubber, sodium alginate, polyvinyl alcohol, polytetrafluoroethylene,   polyacrylonitrile, sodium carboxymethyl cellulose, potassium carboxymethyl cellulose, and a combination thereof; and the conductive agent comprises a material at least one selected from the group consisting of conductive carbon black, acetylene black, Ketjen black, graphene, and a combination thereof.   
     
     
         9 . The electrochemical apparatus according to  claim 8 , wherein based on a total weight of the first negative active material layer, the total weight of the silicon-based material and the graphite in the first negative active material layer is 94% to 96%, a weight of the binder in the first negative active material layer is 2.8% to 4.0%, and a weight of the conductive agent in the first negative active material layer is 0.4% to 1.6%. 
     
     
         10 . The electrochemical apparatus according to  claim 8 , wherein based on a total weight of the second negative active material layer, the total weight of the silicon-based material and the graphite in the second negative active material layer is 94% to 96%, the weight of the binder in the second negative active material layer is 2.8% to 4.0%, and the weight of the conductive agent in the second negative active material layer is 0.4% to 1.6%. 
     
     
         11 . The electrochemical apparatus according to  claim 1 , wherein a single-layer thickness of the second negative active material layer is 40 μm to 60 μm. 
     
     
         12 . An electronic apparatus, comprising an electrochemical apparatus, the electrochemical apparatus comprises a positive electrode, a separator and a negative electrode;
 wherein the negative electrode comprises a negative current collector, a first negative active material layer, wherein the first negative active material layer is arranged on one side of a first portion of the negative current collector; and a second negative active material layer, wherein the second negative active material layers are arranged on two sides of a second portion of the negative current collector, the second portion of the negative current collector is adjacent to the first portion, of the negative current collector,   wherein a ratio of a compacted density of the first negative active material layer to a compacted density of the second negative active material layer is 0.9 to 1.1;   wherein a thickness of the first negative active material layer is 40 μm to 60 μm.   
     
     
         13 . The electronic apparatus according to  claim 12 , wherein the first negative active material layer and the second negative active material layer each independently comprise a silicon-based material and graphite, wherein the silicon-based material is at least one selected from the group consisting of silicon oxide, silicon carbon, and a combination thereof. 
     
     
         14 . The electronic apparatus according to  claim 13 , wherein based on a total weight of the silicon-based material and the graphite, a weight of the silicon-based material in the first negative active material layer and the second negative active material layer is greater than or equal to 5% and less than 100%. 
     
     
         15 . The electronic apparatus according to  claim 13 , wherein a form of the silicon-based material comprises a crystalline state, an amorphous state, or a combination thereof. 
     
     
         16 . The electronic apparatus according to  claim 13 , wherein a particle size Dv 50  of a negative active material in the first negative active material layer is 8.0 μm to 20 μm, and a particle size Dv 50  of a negative active material in the second negative active material layer is 8.0 μm to 20 μm. 
     
     
         17 . The electronic apparatus according to  claim 13 , wherein for the silicon-based material, a ratio of a peak height at a wavenumber of 500 cm −1+−10  cm −1  to a peak height at a wavenumber of 1350 cm −1+10  cm −1  in a Raman spectrum is greater than 0. 
     
     
         18 . The electronic apparatus according to  claim 13 , wherein the silicon-based material further comprises a carbon coating layer. 
     
     
         19 . The electronic apparatus according to  claim 13 , wherein the first negative active material layer and the second negative active material layer each independently comprise a binder and a conductive agent;
 wherein the binder comprises a material at least one selected from the group consisting of polyacrylate, polyimide, polyamide, polyamideimide, polyvinylidene fluoride, styrene-butadiene rubber, sodium alginate, polyvinyl alcohol, polytetrafluoroethylene, polyacrylonitrile, sodium carboxymethyl cellulose, potassium carboxymethyl cellulose, and a combination thereof; and the conductive agent comprises a material at least one selected from the group consisting of conductive carbon black, acetylene black, Ketjen black, graphene, and a combination thereof;   
     
     
         20 . The electronic apparatus according to  claim 13 , wherein based on a total weight of the first negative active material layer, the total weight of the silicon-based material and the graphite in the first negative active material layer is 94% to 96%, a weight of the binder in the first negative active material layer is 2.8% to 4.0%, and a weight of the conductive agent in the first negative active material layer is 0.4% to 1.6%;
 wherein based on a total weight of the second negative active material layer, the total weight of the silicon-based material and the graphite in the second negative active material layer is 94% to 96%, the weight of the binder in the second negative active material layer is 2.8% to 4.0%, and the weight of the conductive agent in the second negative active material layer is 0.4% to 1.6%.